This invention relates generally to oil-hydraulic servo-motors and particularly to those of the type usable on vehicles carrying an appropriate source of oil pressure, principally in connection with the brake system of such vehicle.
The present invention has for its primary object the provision of an improved oil-hydraulic servo-motor of the type described which is simplified in construction and highly reliable in operation compared with conventional forms of such servo-motor and which is designed normally to produce an output hydraulically controlled in response to the limited motion of an associated operating member such as a brake pedal, thus enabling the operator to feel the magnitude of the servo output and avoid any excessive operation, and is also operable to drive the output piston directly under the input of the operator in the event of failure of the associated oil pressure system.
Another object of the present invention is to provide an oil-hydraulic servo-motor of the character described which is further improved in reliability with the associated oil pressure circuit, formed in two independently operable systems, each including a source of oil pressure and arranged so that, even if either of the two oil circuit systems become inoperable due to oil leakage or other failure therein, the output piston in the associated power cylinder can be hydraulically operated in a regular fashion under control of the other, normally operating oil circuit system and, upon failure of both of the two oil circuit systems, such output piston can obviously be operated in a mechanical fashion directly under the operator's input.
These and other objects, features and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings, which illustrate two preferred exemplary embodiments of the invention, both designed for use with a brake system of an automotive vehicle.